Gantry cranes are widely used throughout the world to move heavy equipment within warehouses and storage yards and to load and unload freight vehicles. The gantry cranes have overhead beams on which trolleys with cable winders, sheaves and hooks ride on wheels from side to side to raise, lower and laterally move loads. Carriages are usually provided at the bottoms of legs which support the beams. The carriages move the gantry cranes along a floor or on tracks to approach, lift, reposition and deposit loads as cable winders on the trolleys are activated and the carriages are moved.
Existing gantry cranes are cumbersome and are difficult to move between locations, and cranes are heavy and are difficult to transport to locations and to erect at the locations because of the great weight that is required to provide the strength of the cranes. Lightweight cranes are unsuited for lifting significant loads.
Needs exist for new and improved gantry cranes.